Analysis

What's in a definition? It could well be a health alert

The Health Ministry has decided Singapore will not follow the new, stricter American guideline defining high blood pressure as 130/80 mmHg, opting to stick with 140/90 as the cut-off rate.

There is nothing wrong with this decision, as it is still what most of the world uses. Having said that, the American decision was not arrived at arbitrarily.

It is well researched and reflects the results of long years of study. There is certainly merit to the move, and cardiologists and the ministry would do well to see if any of this could help Singapore get a handle on hypertension which affects one in four adults here.

Like other chronic ailments such as high cholesterol and diabetes, there is no natural hard and fast point at which a person switches from being healthy to sick. The medical fraternity has picked certain measurements, where the risk factors caused by the ailment become significant, to use as the cut-off point.

But damage to the body starts at below these points since in reality, the risk is a continuum, increasing as the blood pressure, cholesterol or sugar levels rise.

In the last National Health Survey, there were three categories each for people with diabetes and cholesterol. There was diabetes, impaired glucose tolerance and normal; and for cholesterol, there was desirable, borderline-high and high.

Surprisingly, for blood pressure, there was just hypertension and normal, with normal being anything below 140/90. Hypertension is determined by a reading of 140/90 - which is what the World Health Organisation (WHO) and, well, practically the rest of the world, also use.

However, WHO and almost everyone else define normal as 120/80 or below. Those whose blood pressure falls between 140/90 and 120/80 are usually referred to as pre-hypertensive. But according to the National Health Survey, they are "normal".

What the Americans have done is to rename half the pre-hypertensives as high blood pressure stage 1, and the other half as having elevated blood pressure. The majority of those with stage 1 high blood pressure do not need medication - only one in five of them would.

How important are such classifications? Whether Singapore adopts the American classification or not, very little will change in the way doctors treat patients, as they are aware risk is a continuum and that other factors, like age, obesity and smoking, need to be considered when deciding whether a person would benefit from medication.

But it could make a world of difference to the layman. Today, someone with a blood pressure reading of 135/85 would happily say he is normal and healthy.

Calling it high blood pressure stage 1 or pre-hypertensive, on the other hand, would alert him that he needs to take action or his health could deteriorate.

So what's in a name? In this case, it could well be a call to action. And that could be a game changer.

A version of this article appeared in the print edition of The Straits Times on December 05, 2017, with the headline 'What's in a definition? It could well be a health alert'. Print Edition | Subscribe